3.22. The Human Development Report 2006, published by the United Nations (UN), showed life expectan- cies by country. For Western Europe, the values reported were Denmark 77, Portugal 77, Netherlands 78, Finland 78, Greece 78, Ireland 78, UK 78, Belgium 79, France 79, Ger- many 79, Norway 79, Italy 80, Spain 80, Sweden 80, Switzerland 80. For Africa, the values reported (many of which were substantially lower than five years earlier because of the prevalence of AIDS) were Botswana 37, Zambia 37, Zimbabwe 37, Malawi 40, Angola 41, Nigeria 43, Rwanda 44, Uganda 47, Kenya 47, Mali 48, South Africa 49, Congo 52, Madagas- car 55, Senegal 56, Sudan 56, Ghana 57.

(a) Which group of life expectancies do you think has the larger standard deviation? Why?

(b) Find the standard deviation for each group. Compare them to illustrate that s is larger for the group that shows more spread.